Many recreational devices are designed to be interactive with a user and, in particular, are configured to measure a length of time between an event and the user's response to the event, or to measure the level of response of the user to the event. For example, in martial arts training, response time is measured between the time a buzzer sounds or a light flashes and the user responds by kicking or hitting a bag or the like. Once the user has responded by hitting the bag or the like, it is desirable to stop the timer so that the user can then measure their response time from the event. The user then attempts to improve their response time by repeating the process. In other applications, it is desirable to measure the strength of a user's impact on a device such as a punching bag, or the number of times the bag is hit.
In designing and manufacturing recreational items for measuring response times and impact and the like, the devices are typically provided with electronics for performing the desired functions. Thus, it is desirable to find a way to provide such electronics which are relatively inexpensive, easy to manufacture, and are easily replaceable.